1. Technical Field
This invention relates generally to a method and apparatus for removing plugs from recesses.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
It's known for a yankee screwdriver-type mechanism to be used to engage and remove a soft material plug from an opening. U.S. Pat. No. 438,410; issued 14 Oct. 1890 to Duffy, discloses a cork removal system including a plunger (O-N-S-Y) supported for translational motion between retracted and extended positions in a housing (M) and a plunger shaft (X) having a twisted section and carrying a threaded gimlet (Y) in the form of a corkscrew. The threads of the gimlet have a thread pitch at least as great as that of the twisted section of the plunger shaft. A lever arm (P) is manually actuated to move the plunger relative to the housing. A plunger handle (O-N) is connected to an aft end of the threaded shaft in a manner that allows for plunger shaft rotation relative to the handle. With the plunger in its extended position, the gimlet protrudes from a forward end of the housing. With the plunger in its retracted position, the gimlet is withdrawn into the housing. The twisted section of the plunger shaft is engaged in a nut (A) carried by the housing and threads of the twisted section are pitched to allow relative axial motion to be converted to rotational motion of the shaft relative to the housing. A rigid frame holds the housing, and also holds a bottle from which a cork is to be extracted, in fixed positions relative to one another. The axial distance that the plunger shaft travels (relative to the frame) to rotate and tap the gimlet into the cork, is equal to the depth that the gimlet reaches in the cork. The Duffy device may thus be used to engage a cork for withdrawal from a bottle by first mounting the bottle in the frame and then tapping the gimlet into the cork by actuating the lever arm to extend and rotate the plunger shaft. The cork may then withdrawn by actuating the lever arm in a reverse direction. This action retracts the plunger shaft, stripping off the cork as the gimlet is drawn back into the housing. However, because the Duffy system requires that the housing and workpiece (bottle) be maintained in a fixed axially-aligned relationship to one another, such a system would be unsuitable for use in applications requiring that a removal tool be handheld, e.g., for use in the extraction of plugs from multiple aircraft skin panel fasteners.
GB Patent No. 602,301 issued May 24, 1948 to Huntley, discloses a “combination tool” comprising a plunger shaft that may include a gimlet having threads pitched to tap. The plunger shaft is supported in a housing for axial motion between retracted and extended positions and is axially spring-loaded toward the retracted position.
GB Patent No. 502,348 issued Mar. 13, 1939 to Bradshaw; and U.S. Pat. No. 942,572 issued Dec. 7, 1909 to Leland et al.; and U.S. Pat. No. 4,224,969 issued Sep. 30, 1980 to Plessner; each discloses a “yankee screwdriver” arrangement including a plunger shaft supported for axial motion between retracted and extended positions in a housing, and threadedly engaged in a nut carried by the housing. In each case the plunger shaft includes threads pitched to allow axial motion to be converted to rotational motion.
U.S. Pat. No. 5,971,939 issued Oct. 26, 1999 to DeSantis et al. discloses a biopsy device including a plunger shaft supported for axial motion in a housing and spring-loaded to a retracted position. The device also includes finger tabs extending from the housing to allow for one-handed control of plunger shaft position relative to the housing.